The popularity of e-readers has reached the point where 10% of Americans use one and another 10% are likely to purchase one in the next six months, according to a poll by Harris Interactive.

The poll of 2,775 adults also produced a major surprise: users of e-readers are reading more than they did before they acquired an e-reader.

"Those who have e-readers do, in fact, read more," said Regina A. Corso, director of the Harris Poll, in a statement. "Overall, two in five Americans (40%) read 11 or more books a year with one in five reading 21 or more books in a year (19%). But among those who have an e-reader, over one-third read 11-20 books a year (36%) and over one-quarter read 21 or more books in an average year (26%)."

The market research firm, which released the study on Wednesday, cautioned that it is still early in the e-reader game to make ironclad projections.

The Harris findings also loosely track the recent sales experience of Amazon's Kindle e-reader; in August Amazon said sales of its latest Kindle in four weeks had surpassed the entire sales of its previous e-reader generation. Amazon's latest Wi-Fi Kindle sells for $139. Its Wi-Fi + 3G is $189.

The Harris poll should also relieve some of the anxieties of the physical book publishing industry, because it showed that users of e-readers are more likely to purchase books. "One in five Americans (21%) say they have not purchased any books in the past year compared to only 8% of e-reader users who say the same," according to Harris.

The poll also put to rest the theory that e-reader users would download more books than they would traditionally purchase, but read at the same level as they did before they had an e-reader. Over half of the poll respondents said they read more with e-readers.

"At the moment, it is too early to tell for sure, but this early evidence is pointing to something good," according to Harris, "People seem to be reading more if they have an e-reader which is something the publishing industry, which has been decline over recent years, is sure to celebrate."

Among 688 respondents, 46% have deployed mobile apps, with an additional 24% planning to in the next year. Soon all apps will look like mobile apps – and it's past time for those with no plans to get cracking.